Spring boot embedded tomcat logs

Found it !! You are now able to see the internal Logs of Embedded Tomcat in your App's Log4j log file with 3 easy steps:

1] add to your pom:

 <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-jul</artifactId>
     </dependency>

2] add to your running arg a new JVM param , e.g:

java -Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager -jar target/demo-0.0.1-SNAPSHOT.jar

3] add to your application.properties:

logging.level.org.apache=DEBUG

Enjoy Life ! :)

Explaination: the problem is because Log4j log levels is not propagated into JUL (which is the actual Logging way Embedded tomcat use) so the above achieves this connection with JUL and Log4j log levels.

Reference: After reading the Spring boot 1.5.10 release notes (which is not required for the solution) i saw the new documentation that shed light how to achive it and explaination about it:

https://github.com/spring-projects/spring-boot/issues/2923#issuecomment-358451260

I struggled a lot,and didnt find anything of my help.Utlimately I had build "WAR" out of my spring boot application.Deploy it to tomcat instance and followed below steps,which redirected all the internal tomcat logs(JULI) logs to my application log file.

1. Delete existing JULI library (CATALINA_HOME/bin/tomcat-juli.jar file) and the existing Tomcat Java Logging configuration file (CATALINA_HOME/conf/logging.properties).

2. Download JULI Log4j Tomcat library (tomcat-juli.jar) from the Tomcat downloads’ Extras section (http://tomcat.apache.org/download-70.cgi). Place the downloaded file to CATALINA_HOME/bin directory.

3. Download Tomcat JULI adapters library (tomcat-juli-adapters.jar) from the Tomcat downloads’ Extras section. Place this file in the CATALINA_HOME/lib directory.

4. Download Log4j (version 1.2 or later), and place the downloaded library file to CATALINA_HOME/lib directory.

5. Create the Log4j configuration file at the following location: CATALINA_HOME/lib/log4j.properties. Check below log4j configuration matching the default Java Logging configuration.

6. Restart Tomcat.

Log4j configuration File Matching the Default Tomcat Logging Settings:

log4j.rootLogger=INFO, CATALINA
//Define all the appenders log4j.appender.CATALINA=org.apache.log4j.DailyRollingFileAppender
log4j.appender.CATALINA.File=${catalina.base}/logs/catalina.
log4j.appender.CATALINA.Append=true log4j.appender.CATALINA.Encoding=UTF-8

//Roll-over the log once per day
log4j.appender.CATALINA.DatePattern='.'yyyy-MM-dd'.log'
log4j.appender.CATALINA.layout = org.apache.log4j.PatternLayout

log4j.appender.CATALINA.layout.ConversionPattern = %d [%t] %-5p %c- %m%n
log4j.appender.LOCALHOST=org.apache.log4j.DailyRollingFileAppender
log4j.appender.LOCALHOST.File=${catalina.base}/logs/localhost.
log4j.appender.LOCALHOST.Append=true log4j.appender.LOCALHOST.Encoding=UTF-8
log4j.appender.LOCALHOST.DatePattern='.'yyyy-MM-dd'.log'
log4j.appender.LOCALHOST.layout = org.apache.log4j.PatternLayout
log4j.appender.LOCALHOST.layout.ConversionPattern = %d [%t] %-5p %c- %m%n
log4j.appender.MANAGER=org.apache.log4j.DailyRollingFileAppender
log4j.appender.MANAGER.File=${catalina.base}/logs/manager.
log4j.appender.MANAGER.Append=true log4j.appender.MANAGER.Encoding=UTF-8
log4j.appender.MANAGER.DatePattern='.'yyyy-MM-dd'.log'
log4j.appender.MANAGER.layout = org.apache.log4j.PatternLayout
log4j.appender.MANAGER.layout.ConversionPattern = %d [%t] %-5p %c- %m%n
log4j.appender.HOST-MANAGER=org.apache.log4j.DailyRollingFileAppender
log4j.appender.HOST-MANAGER.File=${catalina.base}/logs/host-manager.
log4j.appender.HOST-MANAGER.Append=true log4j.appender.HOST-MANAGER.Encoding=UTF-8
log4j.appender.HOST-MANAGER.DatePattern='.'yyyy-MM-dd'.log'
log4j.appender.HOST-MANAGER.layout = org.apache.log4j.PatternLayout
log4j.appender.HOST-MANAGER.layout.ConversionPattern = %d [%t] %-5p %c- %m%n
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.Encoding=UTF-8
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

//Configure which loggers log to which appenders
log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].
[localhost]=INFO,
 LOCALHOST
log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].
[localhost].[/manager]=INFO,MANAGER
log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].
[localhost].[/host-manager]=
INFO, HOST-
MANAGER

You can also check a adapter avaiable on GIT @ link

In your spring boot application,you can make changes like adding and removing jars,folder from embedded Tomcat server Or even adding custom config files to it using TomcatEmbeddedServletContainerFactory.class ,of spring boot.